Structure and method for electrical method of determining film conformality

Abstract

The invention provides a monitor wafer and a method using the wafer to measure the conformality of dielectric films and in particular, for measuring the sidewall deposition thickness of dielectric films.

What is claimed is:  
     
       1. A conformality monitoring kit comprising: 
       a high surface area ratio capacitor;  
       a low surface area ratio capacitor;  
       means for monitoring capacitance, electrically coupled to said capacitors; and  
       means for converting capacitance into conformality, logically coupled to said monitoring means.  
     
     
       2. A conformality monitoring kit, according to  claim 1 , wherein said high surface area ratio capacitor comprises: 
       a first region of semiconductor material;  
       a first region comprising shallow trench isolation defined on said first region of semiconductor material;  
       a first conductive pad deposited on said first shallow trench isolation wherein said first conductive pad has conducting lines and has a high surface area ratio;  
       a first dielectric film deposited on said first conductive pad and lines; and  
       a first array of electrically conductive material disposed on said first dielectric film.  
     
     
       3. A conformality monitoring kit, according to  claim 1 , wherein said low surface area ratio capacitor comprises: 
       a second region of semiconductor material,  
       a second region comprising shallow trench isolation defined on said second region of semiconductor material,  
       a second conductive pad deposited on s aid second shallow trench isolation wherein said second conductive pad has conducting lines and has a low surface area ratio;  
       a second dielectric film deposited on said second conductive pad and lines; and  
       a second array of electrically conductive material disposed on said second dielectric film.  
     
     
       4. A conformality monitoring kit, according to  claim 1 , wherein said capacitance monitoring means comprise MOS test equipment. 
     
     
       5. A conformality monitoring kit, according to  claim 1 , wherein said capacitance converting means comprise an algorithm. 
     
     
       6. A conformality monitoring kit, according to  claim 1 , wherein said high surface area ratio is at least 100:1. 
     
     
       7. A conformality monitoring kit, according to  claim 1 , wherein said high surface area ratio is at least 200:1. 
     
     
       8. A conformality monitoring kit, according to  claim 1 , wherein said high surface area ratio is at least 300:1. 
     
     
       9. A conformality monitoring kit, according to  claim 1 , wherein said low surface area ratio is about 1:1. 
     
     
       10. A conformality monitoring kit, according to  claim 1 , wherein said low surface area ratio is about 0.5:1. 
     
     
       11. A conformality monitoring kit, according to  claim 5 , wherein said algorithm comprises the equation: 
       
         
           Conformality=d per   /d   top   =[C   flat /A flat   ]/{[C   T   −C   flat  ( A   top   /A   flat )]/( A   per )}.  
         
       
     
     
       12. A conformality monitoring kit, according to  claim 5 , wherein said algorithm comprises the equation: 
       
         
           Conformality= F.  ( A   per   /A   flat )×{ C   flat   /[C   T   −C   flat ( A   top   /A   flat )]} 
         
       
     
     
       13. A conformality monitoring kit, according to  claim 1 , wherein said first and said second capacitors are mounted on the same wafer. 
     
     
       14. A conformality monitoring kit, according to  claim 1 , wherein said first and said second capacitors are mounted on separate wafers. 
     
     
       15. A conformality monitoring kit, according to  claim 14 , wherein said shallow trench isolation covers substantially the entire area of the wafer, and wherein said conductive pad covers substantially the entire surface area of said shallow trench isolation. 
     
     
       16. A conformality monitoring kit, according to  claim 1 , wherein said electrically conductive material comprises any conveniently definable highly conductive material. 
     
     
       17. A conformality monitoring kit, according to  claim 1 , wherein said electrically conductive material is a conveniently definable highly conductive material selected from the group consisting of Al, Cu, W, and WSi X . 
     
     
       18. A conformality monitoring kit, according to  claim 17 , wherein said electrically conductive material is disposed in an array of 1-4 millimeter dots. 
     
     
       19. A conformality monitoring kit, according to  claim 1 , wherein said trench isolation comprises any conveniently-definable material having a low dielectric constant. 
     
     
       20. A conformality monitoring kit, according to  claim 1 , wherein said trench isolation is a material having a low dielectric constant selected from the group consisting of silicon dioxide, silicon nitride, and sapphire. 
     
     
       21. A conformality monitoring kit, according to  claim 1 , wherein said conductive pad comprises any conveniently-definable, electrically conductive material. 
     
     
       22. A conformality monitoring kit, according to  claim 1 , wherein said conductive pad is an electrically conductive material selected from the group consisting of n+ doped polysilicon, p+ doped polysilicon, W, Wsi x , Al, and Cu. 
     
     
       23. A conformality monitoring kit, according to  claim 1 , wherein said dielectric film is a silicon oxide or nitride selected from the group consisting Of SiO 2 , Si 3 N4, and SiO x N y . 
     
     
       24. A conformality monitoring kit, according to  claim 1 , wherein said dielectric film is a metal oxide selected from the group consisting of Al 2 O 3 , ZrSiO 4 , TiO 2 , Ta 2 O 5 , ZrO 2 , and other metal oxides. 
     
     
       25. A conformality monitoring kit, according to  claim 1 , wherein said dielectric film is a perovskite. 
     
     
       26. A method of measuring the conformality of a film comprising: 
       providing a first capacitor having a high surface area ratio;  
       providing a second capacitor having a low surface area ratio;  
       providing means of monitoring capacitance of said first and said second capacitors wherein said monitoring means are electrically connected to said first and said second capacitors;  
       providing an algorithm for converting said capacitance into conformality wherein said algorithm is logically coupled to said monitoring means; and  
       converting capacitance into conformality using said algorithm.  
     
     
       27. A method of measuring the conformality of a film, according to  claim 26 , wherein said high surface area ratio capacitor comprises: 
       a first region of semiconductor material;  
       a first region of shallow trench isolation defined on said first region of semiconductor material;  
       a first conductive pad deposited on said first shallow trench isolation wherein said first conductive pad has conducting lines and has a high surface area ratio;  
       a first dielectric film deposited on said first conductive pad and lines; and  
       a first array of electrically conductive material disposed on said first dielectric film.  
     
     
       28. A method of measuring the conformality of a film, according to  claim 26 , said low surface area ratio capacitor comprises: 
       a second region of semiconductor material,  
       a second region comprising shallow trench isolation defined on said second region of semiconductor material,  
       a second conductive pad deposited on said second shallow trench isolation wherein said second conductive pad has conducting lines and has a low surface area ratio;  
       a second dielectric film deposited on said second conductive pad and lines; and  
       a second array of electrically conductive material disposed on said second dielectric film.  
     
     
       29. A method of measuring the conformality of a film, according to  claim 26 , wherein said capacitance monitoring means comprise a MOS tester. 
     
     
       30. A method of measuring the conformality of a film, according to  claim 26 , wherein said algorithm comprises the equation: 
       
         
           Conformality= d   per   /d   top   =[C   flat   /A   flat   ]/{[C   T   -C   flat ( A   top   /A   flat )]/( A   per )}.  
         
       
     
     
       31. A method of measuring the conformality of a film, according to  claim 26 , wherein said algorithm comprises the equation: 
       
         
           Conformality= F . ( A   per   /A   flat )×{ C   flat   [C   T   C   flat ( A   top   /A   flat )]} 
         
       
     
     
       32. A method of measuring the conformality of a film, according to  claim 26 , wherein said high surface area ratio is at least 100:1. 
     
     
       33. A method of measuring the conformality of a film, according to  claim 26 , wherein said high surface area ratio is at least 200:1. 
     
     
       34. A method of measuring the conformality of a film, according to  claim 26 , wherein said high surface area ratio is at least 300:1. 
     
     
       35. A method of measuring the conformality of a film, according to  claim 26 , wherein said low surface area ratio is about 1:1. 
     
     
       36. A method of measuring the conformality of a film, according to  claim 26 , wherein said low surface area ratio is about 0.5:1. 
     
     
       37. A method of measuring the conformality of a film, according to  claim 26 , wherein said first and said second capacitors are mounted on the same wafer. 
     
     
       38. A method of measuring the conformality of a film, according to  claim 26 , wherein said first and said second capacitors are mounted on the separate wafers. 
     
     
       39. A method of measuring the conformality of a film, according to  claim 26 , wherein said shallow trench isolation covers substantially the entire area of the wafer, and wherein said conductive pad covers substantially the entire surface area of said shallow trench isolation. 
     
     
       40. A method of measuring the conformality of a film, according to  claim 26 , wherein said electrically conductive material comprises any conveniently definable highly conductive material. 
     
     
       41. A method of measuring the conformality of a film, according to  claim 26 , wherein said electrically conductive material is a conveniently definable highly conductive material selected from the group consisting of Al, Cu, W, and WSi x . 
     
     
       42. A method of measuring the conformality of a film, according to  claim 26 , wherein the electrically conductive material is disposed in an array of 1-4 millimeter dots. 
     
     
       43. A method of measuring the conformality of a film, according to  claim 26 , wherein said trench isolation comprises any conveniently-definable material having a low dielectric constant. 
     
     
       44. A method of measuring the conformality of a film, according to  claim 26 , wherein said trench isolation is a material having a low dielectric constant selected from the group consisting of silicon dioxide, silicon nitride, and sapphire. 
     
     
       45. A method of measuring the conformality of a film, according to  claim 26 , wherein said conductive pad comprises any conveniently-definable, electrically conductive material. 
     
     
       46. A method of measuring the conformality of a film, according to  claim 26 , wherein said conductive pad is an electrically conductive material selected from the group consisting of n+doped polysilicon, p+doped polysilicon, W, Wsi x , Al, and Cu. 
     
     
       47. A method of measuring the conformality of a film, according to  claim 26 , wherein said dielectric film is a silicon oxide or nitride selected from the group consisting of SiO 2 , Si 3 N4, and SiO x N y . 
     
     
       48. A method of measuring the conformality of a film, according to  claim 26 , wherein said dielectric film is a metal oxide selected from the group consisting of Al 2 O 3 , ZrSiO 4 , TiO 2 , Ta 2 O 5 , ZrO 2 , and other metal oxides. 
     
     
       49. A conformality monitoring kit, according to  claim 1 , wherein said dielectric film is a perovskite. 
     
     
       50. A method for determining critical process parameters, according to  claim 26 , comprising 
       establishing a set of standard process parameters;  
       determining a standard film conformality;  
       establishing an experimental set of process parameters;  
       determining an experimental film conformality; and  
       comparing the experimental conformality to the standard conformality.